Punch



Aug. 15, 1933. c. 'r. BRADsHAw PUNCH Filed Oct. 8, 1931 gill- 12.294441Charles T racSuxJ/U,

norneg Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE PUNCH i jcharles T. Bradshaw, Philadelphia, Pa. Application October 8, 1931.Serial No. 567,742

2 Claims.

This invention relates to improvements in manually operated punches forpunching' holes in sheet material of various kinds.

The object of the invention is to provide a punch of novel, inexpensiveand efficient construction having means whereby the punchings may beeasily and automatically ejected from within the cutting die, and havingmeans whereby the punch may be quickly and accurately centered upon thework or material to be acted upon thereby. i

The invention resides in the elements of the punch and the combinationsof them herein-4 after described and claimed.

In the accompanying drawing, illustrating the invention,

Figure 1 is a side view of a punch showing one form of embodiment of theinvention.

Figure 2 is a side view thereof as seen at right angles to Fig. 1.

, Figure 3 is'a longitudinal section of the punch,

on line 3-3 of Fig. 2.

Figure 41s a transverse section, on line 4 4.

of Fig. 1. 1

- `Figure 5 is a side view of another form of embodiment of theinvention.

Figure 6 is a side view of the punch shown in Fig. 5, as seen at rightangles thereto.

Figure 7 is a longitudinal section of the punch, 30, on une '1 -7 ofFig. 5.

Figure `Sis a transverse section, on line 8-8 of Fig. 5, omitting thespring. r l

Referring to Figs. 1 to 4, inclusive, 2 designates' the body member 4ofthe punch which in this what tapered at one end portion, as illustrated.l

The tapered end portion of the member or bar y 2 has an axial bore 4therein which extends a considerable distance into the member, rand thetapered end of the member is provided with an annular cutting edge5which surrounds the open end of the bore 4 and constitutes the cuttingdie of the punch. The opposite end of the member or bar 2 is adapted toreceive hammer blows to drive the cutting die of the punch through thematerial to be cut or punched in the usual manner when the punch isinservice. Y

A cylindrical plunger 6 is slidably tted within the outerend portion ofthe bore 4 so as to be longitudinally movable therein, and, in thenormal position of the plunger, as shown in the drawing, the lower orouter end surface thereof is at the plane of the cutting edge 5 of the Y.punch or substantially so.

Side Walls of the body member 2 on opposite instance is in the form of acylindrical bar somesides of the bore 4 therein are provided withoppositely-arranged, longitudinally-extending, parallel slots 9 whichopen into the bore and extend through the walls of the member to theexterior thereof.

The inner end portion of the plunger 6 carries a pin 10 which extendstransversely through the same and has its end portions extendingoutwardly from the respective sides of the plunger and into the slots 9.The pin 10 and the walls 65 of the slots 9 serve to limit the extent ofthe longitudinal movement of the plunger 6 within the bore 4,'and theend walls of the slots 9 nearest the cutting edge 5 prevent downward oroutward movement of the plunger l6 beyond its normal po- 70 sition.

A helical spring 11 is housed Vwithin the bore 4 and exerts pressureagainst the inner end wall of the bore and the inner end of the plunger6 and holds the plunger yieldingly in its normal position' from which itmay be moved inwardly against the action of the spring 11` and to whichit will be automatically returned by the spring when inward pressureagainst the plunger is re-4 moved.

The inner end of the plunger 6 is provided with a centrally arrangedprojection 12 which extends into the adjacent end of the spring 11 andholds it in a' central position with relation to the plunger for theproper operation of the spring and plunger and for the prevention ofundue friction between the helices of the spring and the annular wall ofthe bore 4.

The lower or outer end of the plunger 6 is provided with a pointedcentering pin 13 which pro- 90 jects downwardly or outwardly from thecenter ofthe outer end surface of the plunger in axial alinement withthe plunger and the cutting die, as clearly shown in the drawing.

It will now be understood that when the punch is in service the cuttingdie may be easily and quickly centered over the hole to be cut in thematerial to be acted upon by placing the point of the centering pin 13upon or near a suitable dot or mark upon the material. Itwill beunderstood also that when a holeis punched in the material, the pin 13and plunger' 6 will be moved inwardlyA against the pressure of thespring 11 which, when the punch is removed from the material, will movethe plunger outwardly to its normal position and thus automaticallyeject the punchingr from the cutting die.

If the spring 11 should fail to return the plunger to normal positionafter one or more punching operations, and one or more punchings shouldbecome clogged within the cutting die, due to the character of thematerial being acted upon, the plunger 6 may be readily forced back tonormal position to eject the clogged punchings by the aid of a hammer orother tool or instrument applied to one or both of the outer endportionsof the pin which are extended outwardly beyond the slots 9 for thispurpose.

Another purpose of projecting the end portions of the pin 10 outwardlyfrom within the slots9 is that'they prevent the cylindrical body of thepunch from rolling away when it is laid upon a work bench or table whichis not perfectly level,

. connecting the head and handle 16 and extending laterally. from thehandle and longitudinally from the head, as illustrated in the drawing.

lThe head 15 is made tapered and has an axial bore 18 extendingtherethrough and it is pro- .vided with an annular cutting edge 19 whichsurrounds the lower or outer end of the bore 18 and forms the cuttingdie or", the punch.. rJhe outer or upper end of the handle 16 is adaptedto 'receive hammer blows to drive the cutting die through the materialtol be punched. Y

A cylndrical plunger 20 is slidably fitted within the bore 18 of thehead 15 and it is longitudinally movable therein. In the normal positionof the plunger 20, as shown in the drawing, the

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lower or outer end surface. thereof is at the plane ofthe cutting edge19 or substantially so.

"The upper or inner end portion of the plunger 20 extends into the spacebetween lthe head l5 and the handle 16 and it is provided with a pin 2lYwhich extends transversely therethrough and has its end portionsextending. outwardly from the respective sides thereof and is adapted toengage the inner or upper end oi the head 15 and prevent outward or`downward movement of' the plunger beyond its normal position.

TheA inner or lower end portion of the handle 16 is provided with a bore22 in axial alinement.

with andof less diameter than the bore 18 in the Vhead 15, and the inneror upper end portion of the'plungerr 20 is Yprovided withv core `23having a diameter substantially ythe same as the diameter of the handlebore 2,2 and in alinement therewith. v

helical spring 24 extends between the nandie 16 and the plunger 20 andhas its respective end portions housed within the bores 22 and 23. Thespring 24 exerts pressure against the handle 16` and against theplungerv 2() and holds the plunger:l yieldingliy in` its normal positionand from which .it may be moved or pressed inwardly against the','action ,of the spring.

The lower or outer end of theplunger. 20 is provided with a pointedcentering pin 25which projects downwardly or outwardly from the centerof the outer surface of the plunger..

The functions and operations of the plunger 20, spring 24 and centeringpin 25, are the same as the unctions and operations ol the plunger 6,spring 11 and centering pin 13, previously described.

I claim my invention:

l. A punch comprising a body member having a head forming one endportion thereof and a handle spaced from the head in axial alinementtherewith and forming the opposite endportion of the member andconnected to the head by spaced arms which extend longitudinally fromthe head and laterally from the handle, said head having an axial boreextending therethrough and a cutting edge surrounding the outer endthereof, a plunger slidable in the bore and extending into the spacebetweenthe head and the-handle and having an outer end surface in theregion of the plane of the cutting edge in the normal position of theplunger, a pin penetrating the pl erger andprojectingoutwardly therefromwithin'said space and adapted to engage the inner end of said head andprevent outward movement of the plunger beyond its normal position, saidhandle having a bore therein'opening into saidspace and in axialalinement with. and of less diameter than the bore in the head, saidplungerhaving a bore in the inner end portion thereof4 of substantiallythe diameter of the bore in the handle and alined therewith, a helicalspring having its endportions extending into the bores in the handle andtheplunger and acting against plunger to yieidingly'hold it in its nonai position, anda pointed centering pin projecting from the centerof-said end surface.

A punch comprising a body member having a head forming one end portionthereof and a handle spaced. from the head in axial alinesaid head hving an axial bore extending therethrough and a cutting edge surroundingthe outerend thereof, va piunger slidable Yin the bore and extendinginto thespace between the head and the handlerand having an outersurface'in the region of ,the plane of the cutting edge in the normalposition of the plunger and carrying a part projecting laterallythereirom'within said space and adapted` to engage the inner end ci headand prevent outward movement of the plunger beyond its normal position,said handle having a bore therein opening into said space and in axialalinernent with and of less diameter than the bore in said plungerhaving a bore in the inner end portion thereof of substantially thediameter of the bore in the handle and alined therewith. a helicalspring having its end'portions extending into the bores in the handleandplunger and acting against the plungerto yieldingly hold itin itsnormal. position, and a pointed centeringV pin projecting from thecenter of said surface.

CHARLES T. BRADSHAW.

